England went down to a 100-run defeat by Sri Lanka in the second Test at Headingley on Tuesday to lose the series 1-0 after the tourists clung on for a draw at Lord's.

Kevin Pietersen has said an "underlying current of unhappiness" within the England side that developed during the Ashes thrashing in Australia was still at work had played its part in the team's first home Test series defeat by Sri Lanka.

England went down to a 100-run defeat by Sri Lanka in the second Test at Headingley on Tuesday to lose the series 1-0 after the tourists clung on for a draw at Lord's.

The Sri Lanka series was the first since Pietersen, England's all-time leading run-scorer across all formats, had his central contract cancelled by the England and Wales Cricket Board.

That decision, which the ECB didn't explain by any reference to loss of form or fitness, but rather a need to "support" Test captain Alastair Cook, effectively ended the international career of South Africa-born batsman Pietersen.

But hopes results would improve quickly in his absence after the 5-0 Ashes reverse were dashed by Sri Lanka.

And Pietersen, in his latest Daily Telegraph column published Saturday, suggested there was more to England's woes than on-field performance, citing the way in which last man James Anderson broke down in tears after being dismissed off the penultimate ball at Headingley as an example.

"England were in winning positions in both matches but blew it, and I believe that is a symptom of the senior players being very unsettled. They are not turning up for the captain or coach.

"(Stuart) Broad and (Anderson) looked jaded at Headingley. Why? Why was Jimmy so emotional? We have lost a lot of matches in the past but he has never shown such emotion. He has been through tougher times and suffered lower moments but never been in tears before."

"It says to me there is an underlying current of unhappiness.

"The Australia tour was hard. We were beaten up due to a lot of reasons I cannot go into right now, and some of the senior players are still suffering, with the result that they are struggling to offer leadership in the dressing room," added Pietersen, who signed a settlement agreement that allowed the ECB to terminate his central contract before it was due to expire.

Former skipper Pietersen also said the form of current England captain Alastair Cook -- the left-handed opener has gone 24 innings without a Test century -- was having an impact upon his leadership of the team.

"Cook's form will be affecting him," Pietersen said. "I have played with Cooky long enough to know that when that happens he becomes very quiet and introverted. He struggles to handle it. We have all been through it and it does play on your mind."

Shane Warne, a friend and former Hampshire colleague of Pietersen, has said Cook ought to relinquish the captaincy.

But Warne's fellow Australia bowling great Glenn McGrath said Cook ought to remain in post for England's upcoming five-Test series at home to India as there is no obvious candidate to replace him.

"If there's no one that's going to do a better job, and he's happy to do it, then the captaincy should stay with him," McGrath told cricket.com.au.

However, McGrath added Cook needed to be more flexible in the field.

"I like Cooky, and I have a lot of respect for him," McGrath said. "But England are fairly set in their ways.

"They seem to have plan A and then plan B is nearly non-existent -- it's stand back and wait for the opposition to make a mistake.

"I think in this day and age you have to be a little bit more innovative and think on your feet a little bit more."